Christopher J Osborne

Olympus Pen F F.Zuiko Auto-Zoom 50-90mm f/3.5 mounted on an Olympus Pen F

Olympus Pen F F.Zuiko Auto-Zoom 50-90mm f/3.5 mounted on a Sony A7 MkII

Olympus Pen F F.Zuiko Auto-Zoom 50-90mm f/3.5

Cropping needed? Yes
Average 35mm equivalent focal length after cropping: 60-110mm (very roughly! see below for more details)

Zoomed to 50mm

50-90mm f/3.5 image 1 - OOC+EC

50-90mm f/3.5 image 1 - Cropped
Image size: 16.2mp
35mm equivalent focal length: 61mm

50-90mm f/3.5 image 1 - Final
Image size: 16.9mp
35mm equivalent focal length: 61mm

50-90mm f/3.5 image 2 - OOC+EC

50-90mm f/3.5 image 2 - Cropped
Image size: 19mp
35mm equivalent focal length: 56mm

50-90mm f/3.5 image 2 - Final
Image size: 19.4mp
35mm equivalent focal length: 57mm

50-90mm f/3.5 image 3 - OOC+EC

50-90mm f/3.5 image 3 - Cropped
Image size: 16.7mp
35mm equivalent focal length: 60mm

50-90mm f/3.5 image 3 - Final
Image size: 17.1mp
35mm equivalent focal length:60mm

Zoomed to 90mm

50-90mm f/3.5 image 4 - OOC+EC

50-90mm f/3.5 image 4 - Cropped
Image size: 18.6mp
35mm equivalent focal length: 102mm

50-90mm f/3.5 image 4 - Final
Image size: 18.6mp
35mm equivalent focal length: 102mm

50-90mm f/3.5 image 5 - OOC+EC

50-90mm f/3.5 image 5 - Cropped
Image size: 18.9mp
35mm equivalent focal length: 101mm

50-90mm f/3.5 image 5 - Final
Image size: 17.6mp
35mm equivalent focal length: 107mm

50-90mm f/3.5 image 6 - OOC+EC

50-90mm f/3.5 image 6 - Cropped
Image size: 20.2mp
35mm equivalent focal length: 98mm

50-90mm f/3.5 image 6 - Final
Image size: 20.2mp
35mm equivalent focal length: 98mm

Zoomed each focal length in 10mm steps

50-90mm f/3.5 at 90mm - OOC+EC

50-90mm f/3.5 at 80mm - OOC+EC

50-90mm f/3.5 at 70mm - OOC+EC

50-90mm f/3.5 at 60mm - OOC+EC

50-90mm f/3.5 at 50mm - OOC+EC

50-90mm f/3.5 at 90mm - Cropped
Image size: 18.7mp
35mm equivalent focal length: 102mm

50-90mm f/3.5 at 80mm - Cropped
Image size: 18.3mp
35mm equivalent focal length: 91mm

50-90mm f/3.5 at 70mm - Cropped
Image size: 17.3mp
35mm equivalent focal length: 802mm

50-90mm f/3.5 at 60mm - Cropped
Image size: 17.6mp
35mm equivalent focal length: 70mm

50-90mm f/3.5 at 50mm - Cropped
Image size: 18.1mp
35mm equivalent focal length: 58mm

Along with the 150mm f/4 lens, the 50-90mm zoom is another that I have never actually put on the front of a camera before! Like the 150mm, it really isn't a very exciting specification by modern standards for zoom lenses. The zoom ration is very limited at just 1.8x, and this is combined with a very limiting closest focusing distance of 1.5m, so don't even think of trying anything remotely approaching close-up photography with this lens! It's also rather bulky. When this lens was launched zoom lenses were enough of a novelty to make this lens interesting, despite it's obvious limitations. The fact that today it is a very common lens would certainly suggest it sold in large numbers! But these days, compared to the much more interesting lenses in the Pen F range it is unlikely to see much daylight again once it goes back into the cupboard after this little experiment!

The fact that this is a zoom lens also make it rather difficult to write about. The imaging circle does change somewhat though the zoom lens, though not by as much as I was expecting. As you can see by the last series of images shot 10mm steps though-out the zoom range, the imaging circle is at it's largest at the telephoto end of the zoom (18.7mp at 90mm). It then get's smaller as you zoom towards the middle point, reaching it's smallest point in the middle (17.3mp at 70mm) and then start to increase in size again as you zoom towards the short end of the zoom (18.1mp at 50mm). There was some rather anomalous cropping needed on some of the images worked to a finished state, but I think the series of images at 10mm steps through the zoom range give the best idea idea of the cropping needed at various points in the zoom range.

As far as the results go, the sharpness is useable, and the bokeh can get a bit strange (check out the bokeh in image 6 above!). The lens is also susceptible to an odd lightening of the corners in some circumstances. See image 6 again above for an example. Sometimes the lightening is blue-ish in colour, other times white. I'm not sure what is causing this odd effect, but I think internal reflections might be the answer.